MICHAELMAS DAISIES. 



231 



some one indeed ; the more so, as we invariably destroy the inter- 

 mediate steps that have led up to our most advanced forms. 



The number of species of Aster known to botanists may be 

 roundly estimated at something like 250, and of these no less 

 than 130 or 140 inhabit the United States of America, which 

 may be taken as the great headquarters of the genus. It is also 

 well represented in temperate Asia, Siberia, China, Japan, the 

 temperate Himalayas, and throughout Europe, while outlying 

 members are found in South America and Australia, and even 

 Natal and Cape Colony. From the eastern United States come 

 the greater number of our cultivated species, and, although per- 

 fectly distinct in character, comparatively few of the Rocky 

 Mountain or other western types are found in English gardens. 



There are also at present a large number of plants loosely 

 called Michaelmas Daisies— not, indeed, without some show of 

 reason — and which are said to belong to entirely distinct genera. 

 Among these the Erigerons maybe taken as typical. The differ- 

 ence between this genus and Aster is a very arbitrary one, and 

 is based chiefly on the greater number of ligules or ray-florets, a 

 distinction which good cultivation and the careful selection of 

 the fullest new seedling Asters is making every year more arbi- 

 trary still. Boltonia, which now includes some of the old genus 

 Calimeris, differs from Aster chiefly by its short almost palea- 

 ceous pappus, and Felicia and Olearia by their more or less 

 shrubby habit. 



The genus as a whole wants thorough and careful revision, 

 and whoever may be prevailed upon to undertake it will have to 

 begin by admitting that Asters hybridise as freely as the Colum- 

 bine and the Larkspur. If the late Dr. Asa Gray could have 

 admitted that these plants hybridise in cultivation, if not in 

 a wild state as well, he would have spared himself much un- 

 necessary worry. A. Icevis, A. Novi-Belgii, A. paniculatus, and 

 A. longifolius are the four species that are giving us almost all 

 the trouble at Chiswick. Considerably over one-third of the 

 Asters cultivated in our gardens I have no hesitation in saying 

 are distinct garden crosses between A. Icevis and A. Novi- 

 Belgii. The plants we speak of are almost intermediate between 

 the two ; the foliaceous involucral tips of A. Icevis are nearly 

 always present, but, instead of being closely adpressed as in the 

 type, they are often somewhat loose, and always narrower, as in 



